Great, if very nerdy, article at io9 here. They ‘worked with intrepid researchers Ben Vrignon and Gordon Jackson, who helped track down when “the future” was in a random sampling of over 250 works of science fiction (books, movies, TV, and some comics) created between 1880 and 2010’.
That’s less than twenty per decade, so it’s not going to be completely accurate, but still really interesting how trends changed.
Me? I’m not sure I could ever write anything pre-‘Far Future’. And my immediate reaction was actually ‘501 years? That’s not far, that’s near!’
Just me, maybe.